(1) Field of the Invention
The present invention relates to a turning control apparatus for a vehicle.
(2) Description of Related Art
Techniques have been developed for improving safety of vehicles by achieving vehicle-stability during turning maneuvers. For example, the following related document 1 discloses generating yaw momentum of a vehicle based on the yaw-rate of the vehicle by controlling the difference in the driving torque between the left and right wheels to control the motion of the vehicle.    [Related Document 1] Japanese Laid-open Publication H09-86378
However, in reality, it is difficult to generate yaw momentum at a vehicle even if the driving torque difference between the left and right wheels is varied, because the capacity of traction (adhesive friction between the wheel and the road surface) is limited. The capacity of traction is also called as gripping capacity.
Particularly, to prevent over-steering owing to the technique of related document 1, the driving torque may be increased beyond the gripping capacity of the inside wheel. In this situation, it is difficult to run the vehicle in a straight line due to slip of the inside wheel, and then the degree of over-steering is increased in spite of adjusting the driving torque difference between the left and right wheels to prevent over-steering.